Table 1

Inclusion and exclusion criteria with their respective time points

Inclusion criteria	Time point for checking*
7–14 years old	1
at least one episode of headache per week for at least half a year prior to the pre-treatment period	2
At least one musculoskeletal dysfunction identified by the primary investigator as a movement restriction in one or more of the joints suitable for chiropractic manipulation treatment at the time of the initial screening.	3
written informed consent from the holder(s) of custody	1
a mobile telephone in the family and ability to report weekly headache data	1
ability to read and speak Danish at an adequate level to comply with study requirements	2
Exclusion criteria
contraindications for joint manipulation (Additional file 3)	3
receiving any treatment by a health care professional for headache within the last three months. The only exception being prescription pain medication	2
failure to report baseline data during four weeks prior to randomization	2

*Time points for checking inclusion and exclusion criteria: 1 = prior to start of four weeks pretreatment period; 2 = prior to screening visit; 3 = at screening visit